On Mother's Day, Renee Finney's three children – grieving over her May 5 death from cancer – wrote heartfelt letters to their late mom, tied them to balloons and released them to the sky.

They had no idea what kind of answer they'd receive.

"At first I thought they were really dumb, like she's not going to get them, she's not going to read them," Finney's daughter Da-Vion told San Diego's KGTV 10 News.

But someone did find them: On Monday morning, Yvette Melton discovered the balloons on her doorstep in Murrieta, Calif., 30 miles away from where Finney's three kids – Karries, 25, Da-Vion, 18, and David, 16 – released them in San Marcos. The heartfelt letters moved her, especially when she learned by reading them that the family didn't have enough money to bury their mother.

"It was so many things in those letters that inspired me to help," Melton tells PEOPLE. "With a child writing, 'You are up in heaven but we are not able to bury you,' it just touched me. I had to help – it's something people should do."

After researching the names she found in the letters, Melton eventually came across Finney's obituary. She then sprang into action, contacting the local news station with photos of the balloons and letters, and calling her boss – Melton works at Fallbrook-based Color Spot Nurseries Inc. – to get their company involved.

Employees of the nursery raised $2,000 within hours to help cover the cost of the funeral. The family, meanwhile, managed to raise additional funds on Mother's Day weekend by holding bake sales and car washes, and by setting up donation boxes, according to KGTV 10 News.

"My mom had no life insurance and you want to bury your mother the right way – you want to glorify your mother," Karries told the station. "It means everything to my family."

The combined amount, however, still falls short of the $10,000 the family reportedly needs for the funeral.

"We almost lost her body to the state today because there is a certain amount of time where they won't hold the cemetery spot, and we're rushing over there now to beg them to give us more time," Karries tells PEOPLE. "I feel numb, I am so devastated, I was so close to my mom."

Still, the family never realized the letters would reach a stranger, much less someone who was willing to help them. In addition to her office fundraising efforts, Melton has also set up a funding page called Letters to Heaven to support the Finney family.

"It's the right thing," Melton tells PEOPLE. "It's part of being human, helping each other."